+static const struct img_format {
+ img_output_func *output;
+ char name[4];
+ bool enabled;
+} formats[] = {
+#if HAVE_LIBPNG
+ { img_output_png, "png", 1 },
+#endif
+ { img_output_pam, "pam", 1 },
+ { img_output_ppm, "ppm", 1 },
+ { img_output_pbm, "pbm", 1 },
+};
+
+static int lookup_format(const char *fmt)
+{
+ for (size_t i = 0; i < sizeof formats / sizeof formats[0]; i++) {
+ assert(!formats[i].name[sizeof formats[i].name - 1]);
+
+ if (!fmt && formats[i].enabled)
+ return i;
+
+ if (strcmp(formats[i].name, fmt))
+ continue;
+
+ if (!formats[i].enabled) {
+ tool_err(-1, "%s support disabled at build time", fmt);
+ return -1;
+ }
+
+ return i;
+ }
+
+ tool_err(-1, "unknown format %s", fmt);
+ return -1;
+}
+
+bool img_is_masked(unsigned char **mask, unsigned width, unsigned height)
+{
+ unsigned x, y;
+
+ for (x = y = 0; y < height; ++x < width || (x = 0, y++)) {
+ if (mask[y][x] == 0)
+ return true;
+ }
+
+ return false;
+}
+
+int parserange(unsigned frames, char *str, unsigned char *bits)
+{
+ unsigned long start, end;
+ unsigned int i;
+ char *endptr;
+
+ start = strtoul(str, &endptr, 0);
+ if (start >= frames) {
+ tool_err(-1, "frame %lu out of range.", start);
+ return -1;
+ }
+
+ if (endptr == str) {
+ tool_err(-1, "invalid frame range: %s.", str);
+ return -1;
+ }
+
+ switch (*endptr) {
+ case '\0':
+ end = start;
+ break;
+ case '-':
+ end = strtoul(endptr+1, &endptr, 0);
+ if (end >= frames) {
+ tool_err(-1, "frame %lu out of range.", end);
+ return -1;
+ }
+
+ if (endptr == str)
+ end = frames - 1;
+ break;
+ default:
+ tool_err(-1, "invalid frame range: %s.", str);
+ return -1;
+ }
+
+ if (end < start) {
+ tool_err(-1, "invalid frame range: %s.", str);
+ return -1;
+ }
+
+ for (i = start; i <= end; i++) {
+ bits[i / CHAR_BIT] |= 1 << (i % CHAR_BIT);
+ }
+
+ return 0;
+}
+
+int output(unsigned int frameno, const struct img_format *fmt,
+ unsigned char **framedata, unsigned char **mask,
+ unsigned int width, unsigned int height,
+ struct lbx_colour palette[static 256])
+{
+ char name[strlen(outname) + sizeof ".65535.png"];
+ FILE *of;
+ int rc;
+
+ assert(fmt->output != NULL);
+ assert(frameno < 65536);
+ snprintf(name, sizeof name, "%s.%03d.%s", outname, frameno, fmt->name);
+
+ of = fopen(name, "wb");
+ if (!of) {
+ tool_err(0, "failed to open %s", name);
+ return -1;
+ }
+
+ rc = fmt->output(of, name, width, height, framedata, mask, palette);
+ if (rc < 0) {
+ fclose(of);
+ return -1;
+ }
+
+ if (fclose(of) == EOF) {
+ tool_err(0, "error writing %s", name);
+ return -1;
+ }
+
+ if (verbose)
+ printf("wrote %s\n", name);
+
+ return 0;
+}
+
+static int loadoverride(FILE *f, struct lbx_colour palette[static 256])
+{
+ struct lbx_image *overimg = lbx_img_open(f, &lbx_default_fops, NULL);
+ struct lbx_imginfo info;
+
+ if (!overimg) {
+ tool_err(-1, "failed to open override image: %s", lbx_errmsg());
+ return -1;
+ }
+ lbx_img_getinfo(overimg, &info);
+
+ if (!info.palettesz) {
+ tool_err(-1, "override image has no palette.");
+ lbx_img_close(overimg);
+ return -1;
+ }
+
+ if (lbx_img_getpalette(overimg, palette) == -1) {
+ tool_err(-1, "error reading override palette: %s", lbx_errmsg());
+ lbx_img_close(overimg);
+ return -1;
+ }
+
+ lbx_img_close(overimg);
+ return 0;
+}
+
+static int loadpalette(struct lbx_image *img, struct lbx_imginfo *info,
+ FILE *palf, FILE *override,
+ struct lbx_colour palette[static 256])
+{
+ int i;
+
+ /* For sanity. */
+ if (!palf && !info->palettesz && !override) {
+ tool_err(-1, "no palette available.");
+ return -1;
+ }
+
+ /* Default the palette to a wonderful pink. */
+ for (i = 0; i < 256; i++) {
+ palette[i] = (struct lbx_colour){0x3f, 0x00, 0x3f};
+ }
+
+ /* Read the external palette, if any. */
+ if (palf && lbx_img_loadpalette(palf, &lbx_default_fops, palette) != 0) {
+ tool_err(-1, "error reading external palette: %s", lbx_errmsg());
+ return -1;
+ }
+
+ /* Read the embedded palette, if any. */
+ if (info->palettesz && lbx_img_getpalette(img, palette) == -1) {
+ tool_err(-1, "error reading embedded palette: %s", lbx_errmsg());
+ return -1;
+ }
+
+ /* Read the override palette, if any. */
+ if (override && loadoverride(override, palette) == -1) {
+ return -1;
+ }
+
+ return 0;
+}
+
+static int
+decode(struct lbx_image *img, FILE *palf, FILE *override, int fmt, char **argv)
+{
+ unsigned char *framebits;
+ struct lbx_colour palette[256];
+ struct lbx_imginfo info;
+ int ret = EXIT_SUCCESS;
+ int extracted = 0;
+ unsigned int i;
+
+ assert(fmt >= 0 && fmt < sizeof formats / sizeof formats[0]);
+
+ lbx_img_getinfo(img, &info);
+
+ framebits = calloc(1, img->frames / CHAR_BIT + 1);
+ if (!framebits) {
+ return EXIT_FAILURE;
+ }
+
+ /* Figure out what images we're extracting. */
+ if (!argv[0]) {
+ /* extract all images by default. */
+ memset(framebits, -1, img->frames / CHAR_BIT + 1);
+ } else {
+ for (i = 0; argv[i]; i++) {
+ parserange(img->frames, argv[i], framebits);
+ }
+ }
+
+ if (usepalette) {
+ if (loadpalette(img, &info, palf, override, palette) == -1) {
+ ret = EXIT_FAILURE;
+ goto err;
+ }
+ }
+
+ /* Extract the images, in order. */
+ for (i = 0; i < img->frames; i++) {
+ unsigned char **data;
+ unsigned char **mask;
+
+ if (!(framebits[i / CHAR_BIT] & (1 << (i % CHAR_BIT))))
+ continue;
+
+ data = lbx_img_getframe(img, i);
+ if (!data) {
+ tool_err(-1, "error in frame %u: %s", i, lbx_errmsg());
+ ret = EXIT_FAILURE;
+ continue;
+ }
+
+ mask = lbx_img_getmask(img);
+
+ if (!output(i, &formats[fmt], data, mask,
+ img->width, img->height,
+ usepalette ? palette : NULL)) {
+ extracted = 1;
+ }
+ }
+
+ if (!extracted) {
+ tool_err(-1, "no frames extracted.");
+ ret = EXIT_FAILURE;
+ }
+err:
+ free(framebits);
+ return ret;
+}
+